bootp.c revision 84221 
1/*	$NetBSD: bootp.c,v 1.14 1998/02/16 11:10:54 drochner Exp $	*/
2
3/*
4 * Copyright (c) 1992 Regents of the University of California.
5 * All rights reserved.
6 *
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the University of
22 *	California, Lawrence Berkeley Laboratory and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp  (LBL)
40 */
41
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD: head/lib/libstand/bootp.c 84221 2001-09-30 22:28:01Z dillon $");
44
45#include <sys/types.h>
46#include <netinet/in.h>
47#include <netinet/in_systm.h>
48
49#include <string.h>
50
51#define BOOTP_DEBUGxx
52#define SUPPORT_DHCP
53
54#include "stand.h"
55#include "net.h"
56#include "netif.h"
57#include "bootp.h"
58
59
60struct in_addr servip;
61
62static n_long	nmask, smask;
63
64static time_t	bot;
65
66static	char vm_rfc1048[4] = VM_RFC1048;
67#ifdef BOOTP_VEND_CMU
68static	char vm_cmu[4] = VM_CMU;
69#endif
70
71/* Local forwards */
72static	ssize_t bootpsend(struct iodesc *, void *, size_t);
73static	ssize_t bootprecv(struct iodesc *, void *, size_t, time_t);
74static	int vend_rfc1048(u_char *, u_int);
75#ifdef BOOTP_VEND_CMU
76static	void vend_cmu(u_char *);
77#endif
78
79#ifdef SUPPORT_DHCP
80static char expected_dhcpmsgtype = -1, dhcp_ok;
81struct in_addr dhcp_serverip;
82#endif
83
84/* Fetch required bootp infomation */
85void
86bootp(sock, flag)
87	int sock;
88	int flag;
89{
90	struct iodesc *d;
91	register struct bootp *bp;
92	struct {
93		u_char header[HEADER_SIZE];
94		struct bootp wbootp;
95	} wbuf;
96	struct {
97		u_char header[HEADER_SIZE];
98		struct bootp rbootp;
99	} rbuf;
100
101#ifdef BOOTP_DEBUG
102 	if (debug)
103		printf("bootp: socket=%d\n", sock);
104#endif
105	if (!bot)
106		bot = getsecs();
107
108	if (!(d = socktodesc(sock))) {
109		printf("bootp: bad socket. %d\n", sock);
110		return;
111	}
112#ifdef BOOTP_DEBUG
113 	if (debug)
114		printf("bootp: d=%lx\n", (long)d);
115#endif
116
117	bp = &wbuf.wbootp;
118	bzero(bp, sizeof(*bp));
119
120	bp->bp_op = BOOTREQUEST;
121	bp->bp_htype = 1;		/* 10Mb Ethernet (48 bits) */
122	bp->bp_hlen = 6;
123	bp->bp_xid = htonl(d->xid);
124	MACPY(d->myea, bp->bp_chaddr);
125	strncpy(bp->bp_file, bootfile, sizeof(bp->bp_file));
126	bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048));
127#ifdef SUPPORT_DHCP
128	bp->bp_vend[4] = TAG_DHCP_MSGTYPE;
129	bp->bp_vend[5] = 1;
130	bp->bp_vend[6] = DHCPDISCOVER;
131
132	/*
133	 * If we are booting from PXE, we want to send the string
134	 * 'PXEClient' to the DHCP server so you have the option of
135	 * only responding to PXE aware dhcp requests.
136	 */
137	if (flag & BOOTP_PXE) {
138		bp->bp_vend[7] = TAG_CLASSID;
139		bp->bp_vend[8] = 9;
140		bcopy("PXEClient", &bp->bp_vend[9], 9);
141		bp->bp_vend[18] = TAG_END;
142	} else
143		bp->bp_vend[7] = TAG_END;
144#else
145	bp->bp_vend[4] = TAG_END;
146#endif
147
148	d->myip.s_addr = INADDR_ANY;
149	d->myport = htons(IPPORT_BOOTPC);
150	d->destip.s_addr = INADDR_BROADCAST;
151	d->destport = htons(IPPORT_BOOTPS);
152
153#ifdef SUPPORT_DHCP
154	expected_dhcpmsgtype = DHCPOFFER;
155	dhcp_ok = 0;
156#endif
157
158	if(sendrecv(d,
159		    bootpsend, bp, sizeof(*bp),
160		    bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp))
161	   == -1) {
162	    printf("bootp: no reply\n");
163	    return;
164	}
165
166#ifdef SUPPORT_DHCP
167	if(dhcp_ok) {
168		u_int32_t leasetime;
169		bp->bp_vend[6] = DHCPREQUEST;
170		bp->bp_vend[7] = TAG_REQ_ADDR;
171		bp->bp_vend[8] = 4;
172		bcopy(&rbuf.rbootp.bp_yiaddr, &bp->bp_vend[9], 4);
173		bp->bp_vend[13] = TAG_SERVERID;
174		bp->bp_vend[14] = 4;
175		bcopy(&dhcp_serverip.s_addr, &bp->bp_vend[15], 4);
176		bp->bp_vend[19] = TAG_LEASETIME;
177		bp->bp_vend[20] = 4;
178		leasetime = htonl(300);
179		bcopy(&leasetime, &bp->bp_vend[21], 4);
180		if (flag & BOOTP_PXE) {
181			bp->bp_vend[25] = TAG_CLASSID;
182			bp->bp_vend[26] = 9;
183			bcopy("PXEClient", &bp->bp_vend[27], 9);
184			bp->bp_vend[36] = TAG_END;
185		} else
186			bp->bp_vend[25] = TAG_END;
187
188		expected_dhcpmsgtype = DHCPACK;
189
190		if(sendrecv(d,
191			    bootpsend, bp, sizeof(*bp),
192			    bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp))
193		   == -1) {
194			printf("DHCPREQUEST failed\n");
195			return;
196		}
197	}
198#endif
199
200	myip = d->myip = rbuf.rbootp.bp_yiaddr;
201	servip = rbuf.rbootp.bp_siaddr;
202	if(rootip.s_addr == INADDR_ANY) rootip = servip;
203	bcopy(rbuf.rbootp.bp_file, bootfile, sizeof(bootfile));
204	bootfile[sizeof(bootfile) - 1] = '\0';
205
206	if (IN_CLASSA(ntohl(myip.s_addr)))
207		nmask = htonl(IN_CLASSA_NET);
208	else if (IN_CLASSB(ntohl(myip.s_addr)))
209		nmask = htonl(IN_CLASSB_NET);
210	else
211		nmask = htonl(IN_CLASSC_NET);
212#ifdef BOOTP_DEBUG
213	if (debug)
214		printf("'native netmask' is %s\n", intoa(nmask));
215#endif
216
217	/* Check subnet mask against net mask; toss if bogus */
218	if ((nmask & smask) != nmask) {
219#ifdef BOOTP_DEBUG
220		if (debug)
221			printf("subnet mask (%s) bad\n", intoa(smask));
222#endif
223		smask = 0;
224	}
225
226	/* Get subnet (or natural net) mask */
227	netmask = nmask;
228	if (smask)
229		netmask = smask;
230#ifdef BOOTP_DEBUG
231	if (debug)
232		printf("mask: %s\n", intoa(netmask));
233#endif
234
235	/* We need a gateway if root is on a different net */
236	if (!SAMENET(myip, rootip, netmask)) {
237#ifdef BOOTP_DEBUG
238		if (debug)
239			printf("need gateway for root ip\n");
240#endif
241	}
242
243	/* Toss gateway if on a different net */
244	if (!SAMENET(myip, gateip, netmask)) {
245#ifdef BOOTP_DEBUG
246		if (debug)
247			printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
248#endif
249		gateip.s_addr = 0;
250	}
251
252	/* Bump xid so next request will be unique. */
253	++d->xid;
254}
255
256/* Transmit a bootp request */
257static ssize_t
258bootpsend(d, pkt, len)
259	register struct iodesc *d;
260	register void *pkt;
261	register size_t len;
262{
263	register struct bootp *bp;
264
265#ifdef BOOTP_DEBUG
266	if (debug)
267		printf("bootpsend: d=%lx called.\n", (long)d);
268#endif
269
270	bp = pkt;
271	bp->bp_secs = htons((u_short)(getsecs() - bot));
272
273#ifdef BOOTP_DEBUG
274	if (debug)
275		printf("bootpsend: calling sendudp\n");
276#endif
277
278	return (sendudp(d, pkt, len));
279}
280
281static ssize_t
282bootprecv(d, pkt, len, tleft)
283register struct iodesc *d;
284register void *pkt;
285register size_t len;
286time_t tleft;
287{
288	register ssize_t n;
289	register struct bootp *bp;
290
291#ifdef BOOTP_DEBUGx
292	if (debug)
293		printf("bootp_recvoffer: called\n");
294#endif
295
296	n = readudp(d, pkt, len, tleft);
297	if (n == -1 || n < sizeof(struct bootp) - BOOTP_VENDSIZE)
298		goto bad;
299
300	bp = (struct bootp *)pkt;
301
302#ifdef BOOTP_DEBUG
303	if (debug)
304		printf("bootprecv: checked.  bp = 0x%lx, n = %d\n",
305		    (long)bp, (int)n);
306#endif
307	if (bp->bp_xid != htonl(d->xid)) {
308#ifdef BOOTP_DEBUG
309		if (debug) {
310			printf("bootprecv: expected xid 0x%lx, got 0x%x\n",
311			    d->xid, ntohl(bp->bp_xid));
312		}
313#endif
314		goto bad;
315	}
316
317#ifdef BOOTP_DEBUG
318	if (debug)
319		printf("bootprecv: got one!\n");
320#endif
321
322	/* Suck out vendor info */
323	if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) {
324		if(vend_rfc1048(bp->bp_vend, sizeof(bp->bp_vend)) != 0)
325		    goto bad;
326	}
327#ifdef BOOTP_VEND_CMU
328	else if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
329		vend_cmu(bp->bp_vend);
330#endif
331	else
332		printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
333
334	return(n);
335bad:
336	errno = 0;
337	return (-1);
338}
339
340static int
341vend_rfc1048(cp, len)
342	register u_char *cp;
343	u_int len;
344{
345	register u_char *ep;
346	register int size;
347	register u_char tag;
348
349#ifdef BOOTP_DEBUG
350	if (debug)
351		printf("vend_rfc1048 bootp info. len=%d\n", len);
352#endif
353	ep = cp + len;
354
355	/* Step over magic cookie */
356	cp += sizeof(int);
357
358	while (cp < ep) {
359		tag = *cp++;
360		size = *cp++;
361		if (tag == TAG_END)
362			break;
363
364		if (tag == TAG_SUBNET_MASK) {
365			bcopy(cp, &smask, sizeof(smask));
366		}
367		if (tag == TAG_GATEWAY) {
368			bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
369		}
370		if (tag == TAG_SWAPSERVER) {
371			/* let it override bp_siaddr */
372			bcopy(cp, &rootip.s_addr, sizeof(swapip.s_addr));
373		}
374		if (tag == TAG_ROOTPATH) {
375			strncpy(rootpath, (char *)cp, sizeof(rootpath));
376			rootpath[size] = '\0';
377		}
378		if (tag == TAG_HOSTNAME) {
379			strncpy(hostname, (char *)cp, sizeof(hostname));
380			hostname[size] = '\0';
381		}
382#ifdef SUPPORT_DHCP
383		if (tag == TAG_DHCP_MSGTYPE) {
384			if(*cp != expected_dhcpmsgtype)
385			    return(-1);
386			dhcp_ok = 1;
387		}
388		if (tag == TAG_SERVERID) {
389			bcopy(cp, &dhcp_serverip.s_addr,
390			      sizeof(dhcp_serverip.s_addr));
391		}
392#endif
393		cp += size;
394	}
395	return(0);
396}
397
398#ifdef BOOTP_VEND_CMU
399static void
400vend_cmu(cp)
401	u_char *cp;
402{
403	register struct cmu_vend *vp;
404
405#ifdef BOOTP_DEBUG
406	if (debug)
407		printf("vend_cmu bootp info.\n");
408#endif
409	vp = (struct cmu_vend *)cp;
410
411	if (vp->v_smask.s_addr != 0) {
412		smask = vp->v_smask.s_addr;
413	}
414	if (vp->v_dgate.s_addr != 0) {
415		gateip = vp->v_dgate;
416	}
417}
418#endif
419